JP2006333406A - Base station, mobile station, packet communication system, and communication control method - Google Patents

Abstract

Provided are a base station, a mobile station, a packet communication system, and a communication control method capable of reducing signaling in a radio section and optimizing a route between mobile terminals.
An affiliated mobile station network layer address obtaining means for obtaining a network layer address of a mobile station belonging to a base station, and a layer 2 for obtaining layer 2 address resolution information for a mobile station belonging to another base station. An address resolution information acquisition unit; and a transfer path determination unit that refers to a network layer address of the packet and determines a packet transfer path based on the network layer address of the mobile station to which the packet belongs and the layer 2 address resolution information. Is achieved.
[Selection] Figure 4

Description

  The present invention relates to a base station, a mobile station, a packet communication system, and a communication control method.

  A mobile communication system defined by 3GPP always transfers a packet via a top-level exchange (GGSN: Gateway GPRS Support Node) regardless of the topological position of the communication partner. For example, as shown in FIG. 1A, packets are transferred via the GGSN even in communication between mobile terminals belonging to the same base station. For this reason, the route becomes redundant.

  On the other hand, as shown in FIG. 1B, a packet communication system compliant with the Internet protocol can perform communication via a base station between mobile terminals belonging to the same base station. For this reason, communication can be performed through an optimum route (see, for example, Non-Patent Documents 1 and 2).

  A packet transfer route on the Internet is created by a route control protocol such as OSPF, RIP, or BGP. The frame transfer destination of Layer 2 is determined by an L2 address resolution protocol such as ARP or Neighbor Discovery Protocol. For example, in a packet communication system compliant with the Internet protocol, a frame below Access Router (AR) is frame-transferred by the Layer 2 protocol. For example, the frame is transferred by a protocol such as Ethernet (registered trademark) (see, for example, Non-Patent Document 3).

  Next, a process in which a mobile terminal (MN: Mobile Node) determines a frame transfer destination in a layer 2 network under AR will be described with reference to FIG.

  When the mobile terminal 1 (MN_1) sends an IP packet addressed to the mobile terminal 2 (MN_2), it needs to find the destination address of the layer 2 frame. MN_1 resolves the destination address of the Ether frame whose destination IP address is MN_2 (0). For example, MN_1 refers to the subnet prefix of the IP address of MN_2.

  When the subnet prefix is different from MN_1 as a result of referring to the subnet prefix of the IP address of MN_1, MN_1 determines that MN_2 exists in a different subnet across the routers. In this case, MN_1 designates the destination address of the layer 2 frame as the MAC address of the AR, and transmits the Layer2 frame. For example, the MN_1 transmits the MAC address of the AR notified in advance by Router Advertisement or the like in the dst field (3-1).

  On the other hand, as a result of referring to the subnet prefix of the IP address of MN_2 as a result of referencing the subnet prefix of MN_2, MN_1 determines that MN_2 is in the same subnet as MN_1. In this case, in order to discover the MAC address of MN_2, MN_1 transmits Neighbor Solicitation within the subnet and requests MN_2 to notify the MAC address (1). Receiving Neighbor Solicitation, MN_2 transmits Neighbor Advertisement describing its own MAC address to MN_1 and notifies MN_1 of the MAC address of MN_2 (2).

  MN_1, which has received Neighbor Advertisement and found the MAC address of MN_2, designates the destination address of the Layer2 frame as the MAC address of MN_2 and transmits the Layer2 frame. For example, the MN_2 transmits the MAC address of the MN_2 notified by the Neighbor Advertisement in the dst field (3-2).

By this method, a packet addressed to MN_2 is transferred through an optimum route without passing through the AR.
J. Postel, “Internet Protocol,” Request For Comments 791, September, 1981. S. Deering and R. Hinden, “Internet Protocol, Version 6 (IPv6) Specification,” Request For Comments 2460, December, 1998. “LAN / MAN CSMA / CD Access Method,” IEEE 802.3, March, 2002. T. Narten, et al., “Neighbor Discovery for IP Version 6 (IPv6),” Request For Comments 2461, December, 1998. 3GPP TS 25.321, “Medium Access Control (MAC) protocol specification,”

  However, the background art described above has the following problems.

  The Layer 2 frame destination address solution described above has been followed in wireless LANs based on the IEEE 802.11 standard developed based on Ethernet (registered trademark).

  However, when the wireless transmission band is limited, there is a problem that signaling for Layer 2 address resolution becomes an overhead in the wireless section.

  In addition, the fact that the header of the Layer 2 frame has fields of a transmission source and a destination address also causes a problem of the header overhead.

  On the other hand, the MAC layer, which is a wireless Layer 2 protocol defined by 3GPP, has only a field that describes the Layer 2 address of the MN in the MAC header field. This has an effect of reducing the overhead of the MAC header and signaling for resolving the Layer 2 frame destination address by transmitting all the Layer 2 frames to the base station regardless of the packet destination. However, as described above, in the 3GPP mobile communication system, the L2 frame transmitted to the base station passes through the GGSN regardless of the destination of the IP packet, so that there is a problem that the route becomes redundant.

  As described above, the route can be optimized in the system in which the wireless LAN access point (AP) is introduced into the Internet. However, the overhead of the wireless section becomes large, and in the mobile communication system defined by 3GPP, the overhead of the wireless section can be reduced, but there is a trade-off that the route becomes redundant.

  Therefore, an object of the present invention is to provide a base station, a mobile station, a packet communication system, and a communication control method that can reduce signaling in a radio section and optimize a route between mobile terminals.

  In order to solve the above problems, a base station of the present invention is a base station that provides wireless access to a mobile station, and belongs mobile station network layer address acquisition means for acquiring a network layer address of the mobile station to which it belongs, A layer 2 address resolution information acquisition means for acquiring layer 2 address resolution information for a mobile station belonging to another base station, a network layer address of the packet with reference to a network layer address of the packet, and the layer 2 One of the features is that it comprises a transfer route determination means for determining a transfer route of a packet based on the address resolution information.

  By configuring in this way, the base station acquires the network layer address of the mobile station to which it belongs, refers to the destination IP address in the IP packet of the received layer 2 frame, and based on the mobile station belonging information Layer 2 frames can be transferred.

  A mobile station according to the present invention is a mobile station on a packet communication system, and includes a network layer address notifying unit that notifies a base station to which a network layer address belongs.

  With this configuration, the network layer address can be notified to the base station to which it belongs.

  The packet communication system of the present invention is a packet communication system comprising a base station and a mobile station, the mobile station comprising network layer address notification means for notifying a base station to which a network layer address belongs, The base station includes an affiliated mobile station network layer address obtaining unit that obtains the network layer address, a layer 2 address resolution information obtaining unit that obtains layer 2 address resolution information to a mobile station belonging to another base station, One of the features is provided with a transfer path determination unit that refers to a network layer address of the packet and determines a transfer path of the packet based on the network layer address of the mobile station to which the packet belongs and the layer 2 address resolution information. .

  With this configuration, the mobile station can notify the base station to which the mobile station belongs, and the base station acquires the network layer address of the mobile station to which it belongs and receives the received layer 2 With reference to the destination IP address in the IP packet of the frame, the layer 2 frame can be transferred based on the belonging information of the mobile station.

  Further, the communication control method of the present invention is a communication control method in a packet communication system comprising a base station and a mobile station, wherein the mobile station notifies a base station to which a network layer address belongs to the network layer address notification step And the base station acquires the mobile layer network layer address acquisition step of acquiring the network layer address, and the other base station notifies the mobile station belonging to the other base station of layer 2 address resolution information. A layer 2 address resolution information notification step, a layer 2 address resolution information acquisition step in which the base station acquires layer 2 address resolution information to a mobile station belonging to another base station, and the base station Refer to the layer address, the network layer address of the mobile station to which it belongs and the layer 2 address Based on the determined information, as one of; and a transfer route determination step of determining a transfer route of the packets.

  In this way, the mobile station can notify the belonging base station of the network layer address, and the base station acquires the network layer address of the belonging mobile station and receives the received layer 2 frame. With reference to the destination IP address in the IP packet, the layer 2 frame can be transferred based on the belonging information of the mobile station.

  According to the embodiments of the present invention, it is possible to realize a base station, a mobile station, a packet communication system, and a communication control method that can reduce signaling in a radio section and optimize a route between mobile terminals.

Next, the best mode for carrying out the present invention will be described based on the following embodiments with reference to the drawings.
In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

  A packet communication system according to an embodiment of the present invention includes nodes and links compliant with the Internet protocol. In this embodiment, a case will be described in which a mobile station such as a mobile node (MN), a base station, and an upper station (AR) is provided as a node.

  In the packet communication system according to the present embodiment, the base station belonging process when the mobile station is activated and the reassignment process to the base station when the handoff is performed are triggered by the base station and the AR. The Layer 2 address resolution information is registered, and the L2 frame is transferred based on the registered Layer 2 address resolution information.

  The mobile station 100 according to the present embodiment will be described with reference to FIG.

  The mobile station 100 includes a transmission / reception unit 102 including an antenna, a storage unit 104, and a processing unit 106 connected to the transmission / reception unit 102 and the storage unit 104. The processing unit 106 includes a network layer address notification unit 108 connected to the transmission / reception unit 102 and the storage unit 104.

  The transmission / reception unit 102 transmits / receives a message. The storage unit 104 stores the network layer address of the mobile station. The network layer address notification unit 108 notifies the base station to which the network layer address of the mobile station belongs.

  Next, the base station 200 according to the present embodiment is described with reference to FIG.

  The base station 200 includes a transmission / reception unit 202 including an antenna, a storage unit 204, and a processing unit 206 connected to the transmission / reception unit 202 and the storage unit 204. The processing unit 206 is an affiliated mobile station network layer address registration unit 208, Layer 2 address resolution information notification unit 210, and layer 2 address resolution information acquisition as an affiliated mobile station network layer address acquisition unit connected to the transmission / reception unit 202 and the storage unit 204. A Layer 2 address resolution information registration unit 212 and a transfer route determination unit 214 are provided as means.

  The transmission / reception unit 202 transmits / receives a message. The storage unit 204 stores an belonging mobile station IP address management table and a Neighbor Cache described later. The belonging mobile station network layer address registration unit 208 registers the network layer address of the belonging mobile station in the storage unit 204. The Layer 2 address resolution information notifying unit 210 notifies the upper node and neighboring base stations of the Layer 2 address resolution information for the mobile station to which it belongs. That is, the base station 200 notifies the AR and the base station in the same subnet of the destination address of the layer 2 to the mobile station 100 as a proxy for the mobile station 100. By doing so, it is possible to reduce radio section signaling and to effectively use radio resources. In addition, the route between mobile stations can be optimized by doing this.

  The Layer 2 address resolution information registration unit 212 stores Layer 2 address resolution information for mobile stations belonging to other base stations on the packet communication system. The transfer route determination unit 214 refers to the network layer address of the packet and determines the transfer route of the packet.

  Next, a method for registering Layer 2 address resolution information will be described.

  First, the operation of the mobile station 100 will be described with reference to FIG.

  The mobile station 100 according to the present embodiment notifies the base station 200 of the network layer address of the mobile station when activated and in the process of (re) attachment processing accompanying handoff.

Network layer address notifying unit 108, when the power of the mobile station (MN_1) 100 is ON (1), during the belonging process to the base station 200 _1, its network layer to the base station 200 ₁ that belongs to The address is notified (2). For example, the network layer address notification unit 108, the L2 Association Procedure, notifies the IP address of the MN_1 the base station (Node B_1) 200 _1.

The network layer address notification unit 108, during the re-assignment processing to the switching destination base station 200 ₂ associated with the handoff, and notifies the network layer address of its own to the base station 200 ₂ that belongs to (7). For example, the mobile station 100 performs a handoff (6), when adapted to belong to the base station (Node B_2) 200 _2, the network address notifying section 108, the L2 Reassociation Procedure, the base station IP address of the MN_1 (Node B_2) to notify 200 ₂ (7).

  Examples of network layer addresses are IPv6 or IPv4 addresses.

By doing so, it is possible to transmit a packet to an arbitrary destination IP address without specifying a destination Layer2 address when forming a Layer2 frame. In this case, for connection with the mobile station 100 and the base station 200 ₁ and 200 ₂ are point-to-point, Layer2 mobile station 100, regardless of the destination IP address, the Layer2 frame to the base station 200 Just send it. For example, as a wireless protocol to which this embodiment can be applied, there is a MAC protocol defined in 3GPP (for example, see Non-Patent Document 5).

  Next, the operation flow of the mobile station 100 when registering Layer 2 address resolution information will be described with reference to FIG.

  The mobile station 100 starts (re) attachment processing to the base station 200 (step S602).

  Next, the network layer address notification unit 108 notifies its own network layer address to the base station to which it belongs (step S604).

  Next, the operation of the base station (Node B) 200 in the method for registering Layer 2 address resolution information will be described with reference to FIG.

  The base station 200 according to the present embodiment notifies the layer 2 address resolution information of the belonging mobile station to the AR 300 and the base station 200 in the same subnet with the belonging process of the mobile station 100 as a trigger. In addition, the base station 200 according to the present embodiment acquires the Layer 2 address resolution information of the mobile station 100 belonging to another base station other than itself.

The belonging mobile station network layer address registering unit 208 manages the belonging mobile station network layer address stored in the storage unit 204 when the mobile station 100 is notified of the network layer address when the mobile station belonging process is performed. The notified network layer address is registered in the table (3). For example, a base station (Node B_1) 200 ₁ of the associated mobile station network layer address registration unit 208, if the network address from the mobile station (MN_1) 100 is notified, the base station (Node B_1) 200 ₁ of the associated mobile station IP The IP address (MN_1 IP address) of the mobile station (MN_1) is registered in the address management table.

  The belonging mobile station network layer address management table is a table in which the network layer address of the mobile station belonging to itself is registered. The entry in the table is deleted when the mobile station performs the withdrawal process from the base station.

The Layer 2 address resolution information notification unit 210 uses the mobile station attribution process as an opportunity to map the network layer address of the mobile station to which it belongs and the data link layer address mapping of the base station (self) to which the mobile station belongs, Layer 2 address resolution information is created and notified to at least one of the AR 300 and base stations in the same subnet (4). For example, a base station (Node B_1) 200 ₁ of Layer2 address resolution information notification unit 210, Proxy Neighbor Advertisement (e.g., see Non-Patent Document 4) is notified by unicast addressed AR. Further, the Layer 2 address resolution information notifying unit 210 may perform multicast within the same subnet as shown in FIG. 7 (4).

  When transmitting to the AR only by unicast, the AR registers the mapping between the MN_1 IP address and the Node B_1 MAC address in the Neighbor Cache. As a result, the mapping (NCE: Neighbor Cache Entry) of the above address is created in the AR as shown in FIG. 5 (5). For example, “MN — 1 IP addr → Node B — 1 MAC addr REACHABLE” is registered in the neighbor cache of the AR.

On the other hand, when the multicast is transmitted in the same subnet, the NCE is created in the base station in the same subnet in addition to the AR as shown in FIG. As a result, the above address mapping (NCE: Neighbor Cache Entry) is created AR and the base station (Node B_2) to 200 ₂ as shown in FIG. 7 (5-a) (5 -b). For example, “MN — 1 IP addr → Node B — 1 MAC addr REACHABLE” is registered in the neighbor cache of the AR and the base station (Node B — ₂ ) 2002. In this way, a route can be optimized between base stations.

  An example of the data link layer address is an IEEE 802.3 MAC address (see, for example, Non-Patent Document 3).

  On the other hand, the Layer 2 address resolution information notification unit 210 receives Neighbor Solicitation from an entity in the same subnet. When the layer 2 address resolution information notifying unit 210 is requested to resolve the layer 2 address of the mobile station to which it belongs due to the neighbor solicitation transmitted from the entity within the same subnet, the layer 2 address resolution information notifying unit 210 transmits the proxy neighbor advertisement. The data link layer address is notified as the destination Layer 2 address of the target mobile station.

  When the Layer 2 address resolution information registration unit 212 receives a Proxy Neighbor Advertisement from another base station in the same subnet, the network layer address of the mobile station notified by the Proxy Neighbor Advertisement and the data link layer address of the source base station Is registered with the NCE.

  Next, the operation flow of the base station 200 when registering Layer 2 address resolution information will be described with reference to FIG. 8A.

  During the attribution process of the mobile station 100, the network layer address of the mobile station is notified (step S802).

  Next, the belonging mobile station network layer address registration unit 208 registers the network layer address of the notified mobile station in the belonging mobile station network layer address management table (step S804).

  Next, the Layer 2 address resolution information notifying unit 210 notifies the AR and the base station in the same subnet of the network layer address of the mobile station to which it belongs and the data link layer address of the base station to which it belongs (step S806).

Next, the Proxy Neighbor Advertisement received the base station (Node B_1) 200 ₁ operation will be described with reference to FIG. 8B.

  When the Proxy Neighbor Advertisement is received from another base station, the Layer 2 address resolution information registration unit 212 registers the network layer address of the mobile station and the data link layer address of the source base station notified by the message in the NCE (step S808). ).

  Next, a method for resolving the Layer2 address will be described.

  In the present embodiment, after the AR receives the packet addressed to the mobile station, the packet arrives at the mobile station (downlink), and when the mobile station transmits the packet and is transferred within the same subnet ( (Up)) and will be described.

  First, processing (downstream) from when an AR receives a packet addressed to a mobile station until the packet arrives at the mobile station will be described with reference to FIG. 9, FIG. 10, and FIG.

  First, the operation of AR will be described.

  The AR 300 uses a method conforming to the Neighbor Discovery Protocol to transfer a packet storing the IP address addressed to the mobile station into an L2 frame. The NCE of the AR is registered to transfer the packet in which the IP address of the target mobile station is stored as the destination, and to transfer the L2 frame with the data link layer address of the base station to which the destination mobile station belongs as the destination. Yes.

For example, a packet addressed to the mobile station (MN_1) 100 ₁ reaches the AR (1). AR retrieves the Layer2 address for the mobile station 100 _first IP address (MN_1 IP addr) from Neighbor Cache. If there is no entry in the Neighbor Cache, the AR transmits Neighbor Solicitation and performs address resolution (2).

In addition, the AR 300 describes the Layer 2 destination address whose address is resolved, that is, the MAC address of the base station (Node B_1) 200 ₁ to which the destination mobile station (MN_1) 100 ₁ belongs in the Ethernet (registered trademark) Frame (3 ).

  Next, the operation flow of the AR when the packet reaches the mobile station after the AR receives the packet addressed to the mobile station (downlink) will be described with reference to FIG.

  The AR receives a packet addressed to the mobile station (step S1002).

  Next, the AR refers to the NC (Neighbor Cache) and resolves the destination address of the L2 frame. In this case, the address is the data link layer address of the base station to which the destination mobile station belongs.

  Next, the operation of base station 200 in the downlink will be described.

The base station (Node B_1) 200 ₁ of the transfer route determining unit 214 receives the L2 frame sent from the AR, references the destination IP address of the IP packet in the frame body. The transfer route determination unit 214 searches whether or not the referred destination IP address is registered in the belonging mobile station IP address management table stored in the storage unit 204. If registered, the transfer path determination unit 214 determines that the destination mobile station belongs to itself, frames the IP packet with a wireless L2 frame, and transfers it to the wireless section.

  On the other hand, if it is not registered, a search is made as to whether or not the destination IP address is registered in the Neighbor Cache stored in the storage unit 204. If registered, the L2 frame is framed to the Layer 2 address designated by the NCE. If it is not registered in the NCE, the countermeasure packet is discarded.

For example, the transfer path determining section 214 of base station (Node B_1) 200 ₁ is, L2 receives a frame, the destination address of the IP packet (MN_1 IP addr) is, the belonging mobile station IP address management table of the base station (Node B_1) Search whether there is any. If it is in the belonging mobile station IP address management table of the base station (Node B_1), it is transferred to the radio section (4). In this case, the transfer route determining unit 214 forwards to the mobile station 100 ₁ and encapsulated in radio L2 frame (5).

  Next, the operation flow of the base station in the downlink will be described with reference to FIG.

  First, an L2 frame is received (step S1102).

  Next, the transfer path determination unit 214 refers to the destination address of the IP packet in the received L2 frame body (step 1104).

  Next, the transfer path determination unit 214 determines whether or not there is a registration in the belonging mobile station network layer address management table (step S1106).

  If there is a registration in the belonging mobile station network layer address management table (step S1106: YES), the transfer path determination unit 214 frames it into a wireless L2 frame and transfers it to the wireless section (step S1108).

  On the other hand, when there is no registration in the belonging mobile station network layer address management table (step S1106: NO), the transfer path determination unit 214 determines whether there is a registration in the NC (step S1110).

  If the NC is registered (step S1110: YES), the transfer path determination unit 214 creates and transfers an L2 frame to the data link layer address registered in the NCE (step S1112).

  On the other hand, if the NC is not registered (step S1110: NO), the transfer path determination unit 214 discards the received L2 frame (step S1114).

  Next, the operation of mobile station 100 in the downlink will be described.

  When the mobile station receives the L2 frame and confirms that the frame is addressed to itself from the L2ID in the frame, the mobile station raises an IP packet to L3.

  Next, processing (uplink) in which the mobile station transmits a packet and then is transferred within the same subnet will be described with reference to FIGS.

  First, the operation of the mobile station 100 in the uplink will be described.

  When the mobile station 100 transmits a packet to an arbitrary destination IP address, a wireless L2 frame describing the L2 ID of the mobile station is transmitted to the base station regardless of the destination. Thus, there is no need to perform the Layer 2 address resolution of the destination IP address in the wireless section like a wireless LAN such as IEEE 802.11.

For example, the mobile station (MN_1) 100 ₁ encapsulates at radio L2 frame is transferred to the base station _{(Node B_1) 200 1 (1} ). In other words, irrespective of the destination IP address, and transfers to the base station (Node B_1) 200 _1. In addition, there is no need to resolve the Layer2 destination address using Neighbor Discovery Protocol or the like.

  Next, the operation flow of the mobile station 100 in the uplink will be described with reference to FIG.

  An IP packet is received from Layer 3 (step S1302).

  Next, a wireless L2 frame is transmitted to the base station 200 regardless of the destination of the IP packet (step S1304).

  Next, the operation of base station 200 in the uplink will be described.

The base station 200 ₁ that receives the L2 frame from the wireless link, refers to the destination address of the IP packet of the frame in the body in the L2 frame received. It is searched whether or not the referred destination IP address is registered in the belonging mobile station IP address management table stored in the storage unit 204. If registered, it is determined that the destination mobile station belongs to itself, and the IP packet is framed with a wireless L2 frame and transferred to the wireless section (4).

For example, when receiving the L2 frame from the wireless link, the transfer route deciding section 214 of base station 200 _1, the destination address of the IP packet, for example, CN IP addr is, the base station (Node B_1) 200 ₁ of the associated mobile station IP address Search whether it is in the management table. If it exists, the transfer path determination unit 214 determines that it belongs to the same base station, and transfers it again to the radio section using the wireless L2 frame. In this case, the transfer route determination unit 214 sets the L2 ID to the ID of the destination CN.

On the other hand, the destination address of the IP packet, if the base station (Node B_1) 200 not registered in the _first associated mobile station IP address management table, as shown in FIG. 14, the Neighbor Cache, which stores in the storage unit 204 It is searched whether the destination IP address is registered in. If registered, the L2 frame is framed to the Layer 2 address designated by the NCE (2).

For example, the transfer path determining section 214, the destination address of the IP packet, for example, CN IP addr is, searches whether the base station (Node B_1) 200 ₁ of the associated mobile station IP address management table and Neighbor Cache. If it exists in the Node B_1 Neighbor Cache, the MAC address (Node B_2 MACaddr) of the Node B to which the CN belongs is described, framed with Ethernet (registered trademark), and transferred (2).

Whether transferred receives the IP packet the base station (Node B_2) 200 _2, the destination address of the IP packet, for example, CN IP addr is in the base station (Node B_2) 200 ₂ of the associated mobile station IP address management table (3). The destination address of the IP packet, when in the base station (Node B_2) 200 ₂ of the associated mobile station IP address management table, and transfers the CN encapsulated in radio L2 frame (4).

  If the destination address of the IP packet is not registered in the NCE, it is determined that the destination address exists ahead of the AR, and as shown in FIG. 15, the L2 frame with the AR data link layer address as the destination Is created and transferred to the AR (2).

  For example, the transfer path determination unit 214 searches whether the destination address (CN IP addr) of the IP packet is in the mobile station IP address management table of the base station (Node B_1). If it does not exist, the MAC address of the AR is described and framed with Ethernet (registered trademark).

  Next, the operation flow of the base station 200 in uplink will be described with reference to FIG.

  First, a wireless L2 frame is received (step S1602).

  Next, the transfer path determination unit 214 refers to the destination address of the IP packet in the L2 frame body (step S1604).

  Next, the transfer path determination unit 214 determines whether or not there is a registration in the belonging mobile station network layer address management table (step S1606).

  When there is a registration in the belonging mobile station network layer address management table (step S1606: YES), the transfer path determination unit 214 frames it into a wireless L2 frame and transfers it to the wireless section (step S1608).

  On the other hand, when there is no registration in the belonging mobile station network layer address management table (step S1606: NO), the transfer path determination unit 214 determines whether there is a registration in the NC (step S1610).

  If the NC is registered (step S1610: YES), the transfer path determination unit 214 creates and transfers an L2 frame addressed to the data link layer address registered in the NCE (step S1612).

  On the other hand, when there is no registration in the NC (step S1610: NO), the transfer path determination unit 214 creates and transfers an L2 frame with the AR data link layer address as the destination (step S1614).

  Next, the operation of the AR in the uplink will be described with reference to FIG.

AR transfers according to the route control table carrying L2 frame received from the base station 200 ₂ itself. As a result, it is transferred to the CN via the IP router network (3).

  In an embodiment of the present invention, an NW such as the Internet is configured by an IP router, and a wireless Layer 2 protocol is used by a MAC protocol method defined in 3GPP. Forward.

  In the present embodiment, the mobile station notifies its own network layer address in the base station attribution process at the time of start-up and the re-association process to the base station accompanying the handoff.

  The base station stores a list of network layer addresses of mobile stations belonging to the base station in a storage device as a table. The base station registers and deletes the network layer address in the table in response to the terminal belonging process and the withdrawal process. In response to the (re) attachment process of the terminal, the base station sends the mobile station's network layer address and the base station's data link layer address to the mobile station to the AR and the base station existing in the same subnet. This is notified as Layer 2 address resolution information of the packet.

  The base station and the AR store the network layer address of the mobile station notified from other base stations and the data link layer address of the base station to which the mobile station belongs as the Layer 2 address resolution information of the packet addressed to the mobile station. Store in Neighbor Cache.

  Further, when the base station receives a Layer 2 address resolution request of the mobile station belonging to itself from the AR, the base station notifies the AR of the network layer address of the mobile station to which it belongs and the data link layer address of the base station. The base station to which the L2 frame has been transferred refers to the destination address of the IP header in the frame, and determines the transfer path of the L2 frame based on its own address list table. In this way, effective use of radio resources and route optimization can be realized.

  The base station, mobile station, packet communication system, and communication control method according to the present invention can be applied to a packet communication system.

It is explanatory drawing which shows the packet transfer path | route of a 3G mobile communication system. It is explanatory drawing which shows the packet transfer path | route of the internet. FIG. 3 is a schematic diagram illustrating a layer 2 destination address resolution method. It is a block diagram which shows the mobile station concerning one Example of this invention. It is a block diagram which shows the base station concerning one Example of this invention. It is explanatory drawing which shows the layer 2 destination address resolution information notification method concerning one Example of this invention. It is a flowchart which shows operation | movement of the mobile station concerning one Example of this invention. It is explanatory drawing which shows an example of the multicast transmission of Proxy Neighbor Advertisement concerning one Example of this invention. It is a flowchart which shows operation | movement of the base station concerning one Example of this invention. It is a flowchart which shows operation | movement of the base station concerning one Example of this invention. It is explanatory drawing which shows the downlink packet transfer in the packet communication system concerning one Example of this invention. It is a flowchart which shows operation | movement of the high-order station concerning one Example of this invention. It is a flowchart which shows operation | movement of the base station concerning one Example of this invention. It is explanatory drawing which shows an example of the packet transfer in communication between the terminals under the same base station concerning one Example of this invention. It is a flowchart which shows operation | movement of the mobile station concerning one Example of this invention. It is explanatory drawing which shows an example of the packet transfer in communication between the terminals under different base stations concerning one Example of this invention. It is explanatory drawing which shows an example of the packet transfer in communication between the terminals under different AR concerning one Example of this invention. It is a flowchart which shows operation | movement of the base station concerning one Example of this invention.

Explanation of symbols

100 Mobile station 200 Base station 300 Upper station

Claims (10)

A base station that provides wireless access to a mobile station:
Belonging mobile station network layer address obtaining means for obtaining the network layer address of the belonging mobile station;
Layer 2 address resolution information acquisition means for acquiring layer 2 address resolution information for mobile stations belonging to other base stations;
Transfer path determining means for determining a packet transfer path with reference to the network layer address of the packet and based on the network layer address of the mobile station to which the packet belongs and the layer 2 address resolution information:
A base station comprising: The base station according to claim 1, wherein:
The belonging mobile station network layer address obtaining means obtains the network layer address of the mobile station in the belonging process to the own base station when the belonging base station to which the mobile station belongs and when the belonging base station is switched by handoff. A base station characterized by collecting. In the base station according to claim 1 or 2:
Layer 2 address resolution information notifying means for creating layer 2 address resolution information for the mobile station to which it belongs and notifying at least one of the upper node and the neighboring base station;
A base station comprising: In the base station according to claim 3:
The layer 2 address resolution information notifying means is configured so that the network layer address of the mobile station to which the mobile station belongs when performing the attribution process to the base station when the mobile station belongs to the base station and the base station to which the mobile station belongs is switched by handoff. And mapping of the data link layer address of the base station to which the mobile station belongs as layer 2 address resolution information to the mobile station, and notifying at least one of the upper router and all base stations in the same subnet A base station. In the base station according to claim 4:
The layer 2 address resolution information notifying means transmits the Proxy Neighbor Advertisement to at least one of the upper router and all base stations in the same subnet, so that the network layer address of the mobile station to which the mobile station belongs and the base station to which the mobile station belongs A base station for notifying the mapping of the data link layer address. In a base station according to any one of claims 1 to 5:
The layer 2 address resolution information acquisition means includes a network neighbor address of the mobile station belonging to the other base station and a data link layer of the source base station based on Proxy Neighbor Advertisement transmitted from another base station in the same subnet. A base station that acquires address mapping as route information to a mobile station. A mobile station on a packet communication system:
Network layer address notifying means for notifying the base station to which the network layer address belongs;
A mobile station comprising: The mobile station according to claim 7, wherein:
The network layer address notifying unit notifies the base station to which the network layer address belongs at the time of belonging processing in the case where the belonging base station is switched due to belonging to the base station and handoff. A packet communication system comprising a base station and a mobile station, wherein:
The mobile station
Network layer address notifying means for notifying the base station to which the network layer address belongs;
With
The base station
Belonging mobile station network layer address obtaining means for obtaining the network layer address;
Layer 2 address resolution information acquisition means for acquiring layer 2 address resolution information for mobile stations belonging to other base stations;
Transfer path determining means for determining a packet transfer path with reference to the network layer address of the packet and based on the network layer address of the mobile station to which the packet belongs and the layer 2 address resolution information:
A packet communication system comprising: A communication control method in a packet communication system comprising a base station and a mobile station, comprising:
A network layer address notifying step in which the mobile station notifies a base station to which a network layer address belongs;
An affiliated mobile station network layer address obtaining step in which the base station obtains the network layer address;
A layer 2 address resolution information notification step in which another base station notifies layer 2 address resolution information to a mobile station belonging to the other base station;
A layer 2 address resolution information acquisition step in which the base station acquires layer 2 address resolution information to a mobile station belonging to another base station;
A transfer route determining step in which the base station determines a packet transfer route based on the network layer address of the mobile station to which the base station belongs and the layer 2 address resolution information with reference to the network layer address of the packet:
A communication control method characterized by comprising:

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